U.S. Pat. No. 6,417,175 discloses phosphonocephem derivatives having excellent antibacterial activities for a broad range of Gram-positive and Gram-negative bacteria. These compounds are of the general formula:

wherein R1-R4, Q, X, Y and n are as defined therein. One such compound is 7β-[2(Z)-ethoxyimino-2-(5-phosphonoamino-1,2,4-thiadiazol-3-yl)acetamido]-3-[4-(1-methyl-4-pyridinio)-2-thiazolylthio]-3-cephem-4-carboxylate (molecular formula C22H21N8O8PS4, molecular weight 684.68). The 2008 proposed International Nonproprietary Name (INN) for this compound is ceftaroline fosamil.
U.S. Pat. No. 6,906,055 discloses compounds of formula:

in which X is CH3COOH, CH3CH2COOH or CH3CN and n is 0-5. One such compound (where X is CH3COOH and n is 1) is (6R,7R)-7-[[2(Z)-ethoxyimino-[5-(phosphonoamino)-1,2,4-thiadiazol-3-yl]acetyl]amino]-3-[[4-(1-methyl-pyridinium-4-yl)thiazol-2-yl]sulfanyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-2-carboxylate monoacetate monohydrate, which is also known as pyridinium, 4-[2-[[(6R,7R)-2-carboxy-7-[[2(Z)-ethoxyimino-[5-(phosphonoamino)-1,2,4-thiadiazol-3-yl]acetyl]amino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]thio-4-thiazolyl]-1-methyl-, inner salt, monoacetate, monohydrate (molecular formula C22H21N8O8PS4. C2H4O2. H2O, molecular weight 762.75). The 2006 published USAN name for this compound is ceftaroline fosamil acetate.
When administered, compounds such as ceftaroline fosamil and ceftaroline fosamil acetate are converted in body fluids into the active antibacterial moiety ceftaroline.

Gram-positive bacterial pathogens have revealed an extraordinary ability to develop resistance to antimicrobial agents in the last two decades. Thus, there is a clinical need for new broad-spectrum antimicrobial agents that covers both resistant gram-positive and gram-negative pathogens. Applicants have developed novel cephem compounds that are stable, exhibit good solubility, and are particularly well suited for, e.g., parenteral administration for the treatment of gram-positive and gram-negative bacterial infections.